Closure is a puzzle/platformer title that centers around the concept of light. Through each of the many levels, the goal is to reach the door at the end. Lighting is a key gameplay mechanic, as only platforms and walls illuminated by lightbulbs, or orbs of light the player can carry can actually be touched by the player. The player has to make use of the light source and light orbs in order to get through the area without falling off the bottom.
The game won the Innovation Award at Indiecade. It also won the award for Excellence in Audio at the 2010 Independent Games Festival.
Source: Wikipedia, "http://en.wikipedia.org/wiki/Closure_(video_game)," available under the CC-BY-SA License.